What year and model? What market or nation are you in? Turbo, I guess?

Do you know the fuel injection type?

The thermal nylon ABS ages in under hood conditions. You may be able to get new from Volvo. After market PCV parts are terrible, at least what I got from iPd.

The iPd PCV category page. You may need to select the model or family to find part numbers for what you need.

https://www.ipdusa.com/Catalog/Index?CAT_ID=1067&categorycrumbs=0%2c986&searchwords=

If in USA get part from Tasca Volvo. Cheapest OEM yet shipping may take awhile.

https://tascaparts.com/

Else, clean and rough up with emery cloth and use a appropriate adhesive to securer the two back together. Apply progressive thin layers between cure times.

The small hole is used at idle to continue engine air intake vacuum to draw vapors from the engine oil sump. You may also merely plug the hole to endure a vacuum seal while you get a replacement. What I did on my 1992 as I did the same thing! Until I got a replacement, and learned why we know not to buy some after market items like this!

iPd says they have a kit made of Genuine Volvo parts here:
\https://www.ipdusa.com/products/6657/Flame-Trap-Kit-NON-Turbo-81-87-Genuine-Volvo-6681V-114236

Thanks.
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Beh.